二甲基亞碸 (DMSO)
**二甲基亞碸 (DMSO)** 是一種高度多功能的偶極非質子溶劑，具有獨特的藥理特性。在獸醫學中，它主要被用作**自由基清除劑**和**局部抗發炎**藥物。 * **主要核准用途：** FDA 核准用於局部塗抹，以減輕犬馬因創傷引起的急性腫脹。 * **仿單標示外用途：** 中樞神經系統創傷、腦水腫、短暫性缺血、皮膚潰瘍、燒傷、腸道手術輔助治療、澱粉樣變性，以及限制化療藥物（如小紅莓 doxorubicin）外滲造成的組織損傷。 * **滲透促進劑：** DMSO 能輕易穿透完整的皮膚和生物膜，且不會造成不可逆的損傷。它是一種強效的載體，能促進其他藥物（如皮質類固醇、抗生素、止痛藥）及潛在毒性物質的經皮吸收。 * **臨床要點：** 由於其極易吸水（吸濕性），若暴露於室內空氣中會自行稀釋。必須使用醫療級 DMSO，以避免將工業雜質帶入全身循環。
作用機制: DMSO exhibits a diverse array of pharmacological effects through multiple pathways: * **Free Radical Scavenging:** DMSO directly traps the **free radical hydroxide (OH•)**, while its primary metabolite, **dimethyl sulfide (DMS)**, traps free radical oxygen. This mechanism underpins its anti-inflammatory, cryopreservative, anti-ischemic, and radioprotective qualities. * **Enzyme Inhibition:** Inhibits **alcohol dehydrogenase** → slows the metabolism of alcohol and prevents the conversion of ethylene glycol into its toxic metabolites (making it a potential, though less common, antidote for antifreeze toxicity). * **Prostaglandin Modulation:** Enhances **Prostaglandin E (PGE)** but blocks the synthesis of **PGE2, PGF2-alpha, PGH2, and PGG2**, contributing to its analgesic and anti-inflammatory effects. * **Vascular Effects:** Provokes **histamine** release from mast cells → local vasodilation. It also decreases platelet aggregation. * **Neuromuscular:** Exhibits weak **anticholinesterase** activity.
各物種劑量
- Acute swelling due to trauma · Liberal application should be administered topically to the skin over the affected area 2-3 times daily. Total daily dosage should not exceed 100 grams (or mL of liquid) · topical · q8-12h · Max 30 days
- Adjunctive treatment with surgical colics · 25 mg/kg IV intraoperatively and continued twice daily for the first 24-48 hours post-op. · IV · q12h · 24-48 hours · Administer slowly at 10% concentration.
- Acute rhabdomyolysis · 1 g/kg in a 10% solution of lactated Ringer's or Multisol IV or orally. · IV/PO · once · May be given in the acute stages once hydration status has been restored.
- Adjunctive treatment for laminitis · 0.1-1 g/kg IV, 2-3 times daily · IV · q8-12h · Administer slowly at 10% concentration.
- Acute swelling due to trauma · Liberal application should be administered topically to the skin over the affected area 3-4 times daily. Total daily dosage should not exceed 20 grams (or mL of liquid) · topical · q6-8h · Max 14 days
- Calcinosis cutis · Apply topically to a small area of the body initially (if extensive areas are involved) once daily; and as these areas improve, add new treatment areas. · topical · q24h · Dogs may 'feel bad' if large areas are treated initially, but do not become hypercalcemic.
- Persistent cases of hemorrhagic cystitis (secondary to cyclophosphamide tx) · 10 mL of DMSO medical grade 50% solution is diluted with 10 mL of water and instilled into bladder and removed after 20 minutes. · intravesical · once · 20 minutes
給藥途徑
禁忌症
- Mastocytomas (due to mast cell degranulation)
- Dehydration or shock (diuretic and vasodilatory effects may exacerbate)
- Pregnancy (teratogenic at high doses in some species; use with extreme caution)
不良反應
- Local 'burning', erythema, vesiculation, and dry skin (topical)
- Garlic or oyster-like breath odor
- Lenticular changes (myopia) with chronic high doses
- Hemolysis and hemoglobinuria (IV in horses, especially at >10% concentration or rapid administration)
- Diarrhea, muscle tremors, and colic (IV in horses)
- Rare hepatotoxicity and renal toxicity
藥物相互作用
- Organophosphates / Cholinesterase Inhibitors · Avoid concurrent use due to DMSO's anticholinesterase activity.
- Mercury salts · Can cause fatal mercury intoxication if mixed and applied topically.
- Alcohol · DMSO inhibits alcohol dehydrogenase and may prolong the effects of alcohol.
- Insulin · May be potentiated by DMSO.
- Corticosteroids · May be potentiated by DMSO.
- Atropine · May be potentiated by DMSO.
- Topical toxins or other topical medications · Profound enhancement of systemic absorption of the co-administered substance, potentially leading to systemic toxicity. · major
- Dexrazoxane · DMSO may decrease the activity and efficacy of dexrazoxane; concurrent use should be discouraged. · moderate
監測
- Clinical efficacy (reduction in swelling/inflammation)
- Hemoglobinuria and hematocrit (especially in horses receiving IV therapy)
- Ophthalmic exams (with high doses or chronic use in dogs to monitor for lenticular changes)
過量
The reported LD50 following IV dosage is approximately 4 g/kg in cats and 2.5 g/kg in dogs. **Clinical Signs of Toxicity:** * *Non-lethal doses:* Sedation and hematuria. * *Higher dosages:* Coma, seizures, opisthotonus, dyspnea, and pulmonary edema. **Treatment:** Should an acute overdosage be encountered, treat supportively.
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